Re: [PATCH net-next 3/4] net: macb: Disable one-step mode when TX timestamping is off

[Nicolai Buchwitz <nb@tipi-net.de>]

On 22.9.2026 11:10, Kim Wooseok via B4 Relay wrote:
> From: Kim Wooseok <5mghybrid@khu.ac.kr>
> 
> Switching from HWTSTAMP_TX_ONESTEP_SYNC to HWTSTAMP_TX_OFF turns off
> descriptor timestamping, but leaves NCR.OSSMODE set, so one-step mode
> remains enabled.
> 
> Update OSSMODE for every accepted TX mode and set it only for
> HWTSTAMP_TX_ONESTEP_SYNC. This also clears the previous one-step 
> setting
> when switching to OFF. Since the update mask now always includes
> OSSMODE, drop the check for an empty mask.
> 
> Fixes: ab91f0a9b5f4 ("net: macb: Add hardware PTP support")
> Assisted-by: GPT-6 Astra
> Signed-off-by: Kim Wooseok <5mghybrid@khu.ac.kr>
> ---
>  drivers/net/ethernet/cadence/macb_ptp.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cadence/macb_ptp.c 
> b/drivers/net/ethernet/cadence/macb_ptp.c
> index b6d17fef4..6376b6631 100644
> --- a/drivers/net/ethernet/cadence/macb_ptp.c
> +++ b/drivers/net/ethernet/cadence/macb_ptp.c
> @@ -390,7 +390,7 @@ int gem_set_hwtst(struct net_device *netdev,
>  		  struct kernel_hwtstamp_config *tstamp_config,
>  		  struct netlink_ext_ack *extack)
>  {
> -	u32 ncr_mask = 0;
> +	u32 ncr_mask = MACB_BIT(OSSMODE);
>  	enum macb_bd_control tx_bd_control = TSTAMP_DISABLED;
>  	enum macb_bd_control rx_bd_control = TSTAMP_DISABLED;
>  	int rx_filter = tstamp_config->rx_filter;
> @@ -409,7 +409,6 @@ int gem_set_hwtst(struct net_device *netdev,
>  		ncr_bits |= MACB_BIT(OSSMODE);
>  		fallthrough;
>  	case HWTSTAMP_TX_ON:
> -		ncr_mask |= MACB_BIT(OSSMODE);
>  		tx_bd_control = TSTAMP_ALL_FRAMES;
>  		break;
>  	default:
> @@ -445,11 +444,9 @@ int gem_set_hwtst(struct net_device *netdev,
>  	}
> 
>  	spin_lock_irqsave(&bp->lock, flags);
> -	if (ncr_mask) {
> -		regval = macb_readl(bp, NCR);
> -		regval = (regval & ~ncr_mask) | ncr_bits;
> -		macb_writel(bp, NCR, regval);
> -	}
> +	regval = macb_readl(bp, NCR);
> +	regval = (regval & ~ncr_mask) | ncr_bits;
> +	macb_writel(bp, NCR, regval);
> 
>  	gem_writel(bp, TXBDCTRL, GEM_BF(TXTSMODE, tx_bd_control));
>  	gem_writel(bp, RXBDCTRL, GEM_BF(RXTSMODE, rx_bd_control));

Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>

Thanks,
Nicolai